Project Managers are the people who wish to help out with the Linux Driver Project, but do not want to do the actual programming. They are essential for the project to properly work.
Their tasks are:
help answer initial queries from companies
take ownership of individual driver projects, following them from the initial creation, all the way through to the driver submission process.
match up individual developers with the projects.
work with the developers to help make their life easier in doing the development (work with the company to provide status reports and work with the developer to ensure that they have everything that they need in order to succeed.)